Apparatus for carbon monoxide hydrogenation



H. KQLBEL ET AL 2,868,627

Jan. 13,` 1959 Filed Sept. 21, 1954 r'j'.

@frm/1.1M@ f ||I/6 APPARATUS FOR CARBON MONOXIDE HYDROGENATION Herbert Klbel and Paul AckermanmMoers, Germany Application September 21, 1954, Serial No. 460,999 8 Claims.` (Cl. 23-288) The present invention relates to the design or form of the sump `below the shaft conduits and to the gas feed inlet of the cylindrical tower reaction apparatus as described in German Patent R10,008 IVb/ 12g, in which the whole cross section of the cylinder tower is divided into a plurality or bundle of shaft conduits and is used in this modified form catalytic carbon monoxide hydrogenation with a finely divided catalyst suspended in a liquid medium.

The subdivision of thetotal length of the tower, including the upper gas space, into single `columns for standing, that is non-circulating liquid; is accomplished by shaft conduits with a -diameter of not more than 30 centimeters and of a length 100 centimeters or longer, the subdivision into several single columns beingsuch that they all have a common sump and common upper gas space, according to German Patent R 10,008 IVb/12g; and as described in our copending application Serial No. 481,468 tiled January 12, 1955 with the formation of mainly vertically directed liquid recycle streams and with the result that gas distribution according to quantity and upward gas velocity of gas bubbles is largely equalized almost below a gas rate of 30 liters, at operating conditions, per hour, per centimeter square of reaction space cross section over the total cross section of the reaction space. Therefore, it has `been found expedient to use separately each single shaftcolumn, through which the liquid column is formed, and if possible a separately controlled gas rate, which is fed each time into the single shaft conduits, or at least vertically underneath the shaft conduits into the common liquid sump. From this came the necessity for a gas feed divided uniformly over the total cross section of the lower reaction space with at least one gas exit opening per shaft conduit. It has now been found that a uniform gas distribution can be obtained for such reaction vessels containing a plurality of high, cylindrical shaft conduits by having these shaft conduits terminate above the inlet to leave a lower `reaction space of a diameter the same as the portion of the cylinder around the shaft conduits, with tapering of the bottom of the' lower reaction space below the shaft conduits into a single, axially entering gas entrance opening, where its distance from the lower end of the shaft conduits is at least as long or longerthan the diameter of the cylindrical reaction space across the shaft conduits and the lower reaction space.

The effect of an arrangement according to the invention is particularly surprising for cylindrical liquid columns of 30 centimeters diameter and even larger where, with gas feed in small bubbles uniformly distributed over the whole oor of the liquid, since cylinders usually prevent a uniform distribution of the gas bubbles over the cross section at every height except in the neighborhood ofthe liquid surface. This internal `liquid circulation is promoted presumably bycentral gas feed. It was found thereby that with shaft conduit division of the liquid column the upper inversion point of the liquid cylinder is not below the lower ends of the shaft conduits. Here A United States Patent O er 2,868,627 rPatented Jan. 13, 1959 then the gas distribution is almost uniform over the whole cross section similar to the liquid surface. regulating effect of the suspension of liquid and gas bubbles formed in the shaft columns on the hydrostatic equilibrium at the bases of the shaft conduits packet causes in addition a practically uniform gas distribution to all shaft columns of the conduits.

The form of the taper of the lower reaction space below the shaft 'conduits according to the invention can be formed in different ways, for example, conically or convex or the like, as is shown in Figures 1 and 2.

On the drawings:

Figs. 1 to 5 are taken on line A--A of Fig. 6, to show modifications according to the present invention of the lowermost portion of the reactor, as shown in greater detail in Figs. 7a and 7b of our copending application Serial No. 481,468, tiled January 12, 1955, for Apparatus for Carrying Out Gaseous Catalytic Reactions in Liquid.

Fig. 6 `is a horizontal section on the line B--B of Figs. 1 to 5.

Referring in general to Fig. 4, the cylindrical reactor 1 is conically narrowed at its lower end and has at the bottom a central gas inlet 2. The outlet 3` for the product gas is at the top of the cylinder 1. The reaction space intermediate the top' and bottom of the cylinder 1 is subdivided by shaft conduits 4 containing pipes 7 for heat exchange which have their outlet also at the top of the cylinder 1. The pipe 10 serves for emptying and lling the reactor with catalyst suspension, and the gas is fed in through the gas inlet 2.

It is appropriate to employ a distance 6 betweengas feed inlet 2 and the lower ends 5 ofthe shaft packet 4 of suchlength, namely as large or several times as large as the diameterpof the reactor 1, that the gas stream is sufficiently dispersed. Also, deflection surfaces can Abe installed over the gas feed inlet 2. However, the horizontalcooling liquid feed pipes 4 act as such surfaces to a suicient extent. These are extended appropriately as low as possible below the shaft packet 4, since the heat of reaction also must be drawnoff in the sump 6 below the shaft packet. t

The ratio of the free cross sectional area of the gas feed inlet nozzle 2 and the reaction space, in the height of the cylinder, may lie in the reactor of this invention between l and 10 and about 1 and 10,000, depending on the absolute size of the reactor 1 and the thruput per unit area in units of volume of synthesis gas relative to the freev reaction space cross section. The practical cross sectional thruput for carbon monoxide hydrogenation with suspended iron catalysts at synthesis pressures between about 5 and 25 atmospheres is preferably in the range of 5 and 200 liters synthesis gas per hour and per square centimeter of reaction space cross section under operating conditions.

The ratio of nozzle 2 cross section to reaction space cross section B B is chosen for the total range of the cross sectional thruput in such a manner that the linear velocity in the gas feed inlet opening 2 is between 2 and 400 meters per second, preferably 5 and 200 meters per second. It is advantageous to choose, for larger reaction space diameters, a relatively smaller nozzle cross section, whereby the linear gas velocity correspondingly is increased also with equal thruput of synthesis gas per cross section. Because the distance between nozzle 2 and lower ends 5 of the shaft packet is increased, according to the invention, corresponding to the diameter of the reaction space, a correspondingly increased gas velocity is also desired, since in the sump 6, which may be up to 5, meters high, a vigorous turbulence of the liquid is to be established.;

Reaction spaces of large diameter are also advantageously kept larger in height, for example, 25 meters The i height at 2.5 meters diameter. In order to obtain the same space velocity with synthesis gas and consequently the same space time yield of reaction products, such high reactors.- canbe.l operatedl with higherr cross. sectional thruput than` lower` reactors without.. increasing` the catalystload at, the same concentration. By. increasing the cross sectionalthruputone .is abletofdistribute; thev zone. of reaction, which for example, fory a cross, sec. tional thruput oflO operational.1iters per houris only about 2 meters uniformlyr over the total height ofthe reaction space. An increasein temperature from bottom to topwith relativelyplow.temperature in the `oven sump 6, which can. be. obtained-for example, :according to t the: German Patent,4 R.l 11,327v IVd/.l2.0,` is.. advantageous. in

the same sense.

The suspendedfrcatalyst` is; uniformly distributed over the ftotal Asump 6 volurneby. the strong circulation of z the liquid medium, lwhich occurs.- accordingv to,4 the invention in ,the-entire sump volume, sothat also` a, uniform .feed of catalystisfassured to the single. shafts of -theuconduitsz 4.

Especially stagnant spaces, lacking4 motion, aree. avoidedt by; the ytapering ofthebottom .of the lowerreaction space part of the column 1 according to the invention and thereby` catalyst deposition. is, avoided.

In place;v of the'conical taper as inFigure 1, it isalso lpossible'to use;.advantageously a" taper, fitted tothe liquid circulation movement,v of thet type shown. in Figure 2, where, by the .lengtheninggof i the.r nozzle; 2,. so, that it ex,-

tends into; the; lowerreaction `space 6,`thecirculatingL movement can be'effectivelyI assisted.

One also mayv employ,ginv.addition` to the nozzle 2 whichr.is,extendedinto theglowerpreaction space 6, concentric guiding vanes 11, perhaps-in themannershown arranged@advantageouslyrso:that between tit andthe in sideqwall 12y o'f;the -lowerfpart of; the reaction vessel there:

isfformedl a freerannular space 13 for the liquid medium, which,y narrows, toward the top t and has.-y the largest. con traction at about the upper'edge114 ofthe ,gas feedtube.

From this point on the guidingvane-,mayl be; provided. with an attachment 15, which expands` upwardlylikev a,

venturi, as for example, according. to Figures 4a, 4b,- and 5, where the opening angle is. advantageously be.- tween 50 and 120.

f A strong suction or aspirating effectl is exerted by; the gas stream with this arrangement, wherebyl the liquid, is circulated with increased velocity. Thereby one elfects a forced circulation of', the catalyst suspension, which can be largely regulated. Since the energy necessary is brought into the system,V almost exclusively by the synthesis gas, oneis: able to` increasethe Velocity of the-v liquid circulation to, suchv an extent, by increasing the gas velocity whereby apressure drop before and behind theV nozzle of 0.2-1 atm. or more takes place, that a considerable part of thepgas that is mixed` above. the;

nozzle 2 with the liquid is -carried past the nozzle with the liquid in circulation. The effect of this isan already almost uniform, division of; the; gassinto little-.bubbles in theazouefbelowrfthe shaftsgrofthecconduits-'in the -vessel l.

The gasl distributionaccording to-theinventiony may.

2v and up to 20 times as large as the sum of the smallest free cross section of the gas feed nozzle 2 and the annular space 13.between it and the guiding vane.

We claim:

1. A reactor for the hydrogenation of carbon monoxide by a catalyst suspended in a liquid medium, comprising: an upright cylinder; a plurality of shaft conduits mounted in said cylinder to extend upright axially thereof and adapted to contain said catalyst in the liquid medium; a gas inlet to the interior ofthe cylinder at a level below the bottoms of the shaft conduits; said shaft conduits having theirflowerl-endsterminate in said cylinder at a distance above the gas-inlettheretoso as to have the gas inlet spaced frornrthelower ends. of said shaft conduits a distance at least as great as the diameter of the cylinder around-theshaft conduits'andleave a lower reaction space between said lowererrdsof the shafttconduits and the gas inlet of the same diameter as the portion of the cylinder around the shaft conduits; and the bottom of said lower reaction space being tapered to said gas inlet and said gas inlet also.beingrtaperedl to,.p r,o.videay single axially directed stream of, 'gas into. saidvlower reaction. space,-y

whereby;` said.. stream. induces, circulation within said lower, reaction space .toy feed -gas into said shaft, conduits uniformly;

2. Reactor accoi'diing-,toclaim".1whereinl the tapered' gas inlethlsA a. cross-sectionalarea such that the ratio o f thefr'eecrosssectionalareaof,thegas;inlet to the reac.- tion space, in the height of the cylinder, falls betweerrl and l0and land 10,000J andtheinletdischarges gasat avelocitymf 2101400.- meters .perA second with a crosse sectional` throughputof 5.. to..` 200. operational liters, of

gas per4 hour. persquare.- centimeter of ,reaction space.

3.Reactoraccording to: claim 2; whereinthe. gas inlet,

is;.extended into.v the. lower reaction space.y

4. Reactor.. according., tQcIairn.V .3,` wherein a .ring-shaped; ventu 1". i-=l guiding-vane is;concentr;ically mounted. above. saidgastinlet,and'textendsg into the,A lower reaction Ispace.

Withtatfreespae, between the guidingvane` and the inf sidefwall, of.v said. lower., reaction;Y space and with an annulanfreespace between, the, interior of saidvane andthe gasinlet, for circulation of. said liquidgmedium by` said.

gas.A

5. Reactor accordingl to-claim 4, wherein the guidingA vane is provided .patfits upper edge, with an openingangle of. at least50 andup to about 120;

"tionmof .the gas inlet andl thevv annularl space between, the gas inlet and theguiding.k vane..

7, Reactor.y according to-claim, 1, wherein the ratio ofl the freey crosssectionalarea of the gas inlet to the reaction space,` inthe heightof the cylinder, is between 1 and l0V and l and l,().,000 andV a linear gas velocity of v5 to 2,()0meter-sg. pen secondi isa-available at said gas inlet= with aveross-sectional` throughput of 5 to 200 operational larger than .'thediameter ofgthe cylindrical reactiony space;

References-Cited in the file of thispatent 1,1, ,wherein the lower., ntlsfof seid,Shaft.20D-duit,y 

1. A REACTOR FOR THE HYDROGENATION OF CARBON MONOXIDE BY A CATALYST SUSPENDED IN A LIQUID MEDIUM, COMPRISING: AN UPRIGHT CYLINDER; A PLURALITY OF SHAFT CONDUITS MOUNTED IN SAID CYLINDER TO EXTEND UPRIGHT AXIALLY THEREOF AND ADAPTED TO CONTAIN SAID CATALYST IN THE LIQUID MEDIUM; A GAS INLET TO THE INTERIOR OF THE CYLINDER AT A LEVEL BELOW THE BOTTOMS OF THE SHAFT CONDUITS; SAID SHAFT CONDUITS HAVING THEIR LOWER ENDS TERMINATE IN SAID CYLINDER AT A DISTANCE ABOVE THE GAS INLET THERETO SO AS TO HAVE THE GAS INLET SPACED FROM THE LOWER ENDS OF SAID SHAFT CONDUITS A DISTANCE AT LEAST AS GREAT AS THE DIAMETER OF THE CYLINDER AROUND THE SHAFT CONDUITS AND LEAVE A LOWER REACTION SPACE BETWEEN SAID LOWER ENDS OF THE SHAFT CONDUITS AND THE GAS INLET OF THE SAME DIAMETER AS THE PORTION OF THE CYLINDER AROUND THE SHAFT CONDUITS; AND THE BOTTOM OF SAID LOWER REACTION SPACE BEING TAPERED TO SAID GAS INLET AND SAID GAS INLET ALSO BEING TAPERED TO PROVIDE A SINGLE AXIALLY DIRECTED STREAM OF GAS INTO SAID LOWER REACTION SPACE, WHEREBY SAID STREAM INDUCES CIRCULATION WITHIN SAID LOWER REACTION SPACE TO FEED GAS INTO SAID SHAFT CONDUITS UNIFORMLY. 